A conventional brushless generator is advantageous as its structure is simple. However, a disadvantage of the conventional generator is that the inner stator of such a generator is mounted on its rear cover. With a large current output over a long interval, the generator coil overheats. As the heat-dissipating property of the generator interior is poor, the maximum output current must be limited to prevent overheating. As a result, such generators are often unable to meet practical requirements.
Attempts have been made to improve such brushless generators. One such attempt is described in Japanese patent publication number 53-93313. Described in that patent publication is a generator with an internal fan, the generator being fitted with ventilating holes. However, the improvement provided by the ventilating holes is not very significant, as the generator's fundamental structure is not varied, and further use of an additional fan makes the generator volume large and thus undesirable.
An object of the present invention is to provide an improved brushless generator able to deliver large current over prolonged periods without overheating, the improved generator having good ventilating and heat-dissipating properties enabling it to work normally under adverse circumstances.